1. Field of the Invention
The present invention relates to a calibration device for apparatus for filling a gas such as hydrogen gas, and more particularly to a calibration device capable of efficiently and safely measuring weight and quantity of a gas such as hydrogen gas filled at high pressure.
2. Description of the Related Art
Gas meters installed in gas stations are obliged to take flow rate verification every seven years to maintain fair business dealing, and it is requested that instrumental error of the flow meter is within ±0.5 percent. To such request, the applicant proposes a gas meter with inspection mechanism of flow meters in Japanese Patent Publication No. Heisei 07-33197.
In recent years, as a countermeasure for environmental issue, fuel-cell automobiles using hydrogen as fuel have been developed, accordingly hydrogen filling apparatus and calibration devices for hydrogen filling apparatus have been investigated.
In a conventional calibration device for the hydrogen filling apparatus increases temperature of hydrogen when hydrogen is filled from a fuel gas filling apparatus such as the hydrogen filling apparatus to the calibration device, which causes expansion of hydrogen to increase its pressure. Therefore, while the hydrogen is filled in the calibration device, it is necessary to confirm temperature, pressure and the like by eyesight to consider safety of the calibration device.
But, a calibration device for the hydrogen filling apparatus for confirming temperature, pressure and the like by eyesight while the hydrogen is filled in the calibration device, and for efficiently and safely measuring weight of filled hydrogen gas has not been produced yet.
The contents of Japanese Patent Publication No. Heisei 07-33197 is incorporated herein by reference in its entirety.